If you have been working on playing scales, chords, and harmony in general, this set is the next step towards getting your ears and fingers coordinated. This set is a continuation of Volume 3, but in much more depth. Set contains 5 Turnaround Tracks, 6 Cycle Tracks, Coltrane Blues, Some of The Things I Am (an exercise in substitute II/V7's), Joy Stick, 6 II/V7 Tracks, Coltrane Changes in All 12 Keys, Bb Rhythm Changes (slow tempo), and Guess What Key I'm In. Twenty-three tracks in all and almost all go through all 12 keys!!